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At the nanoscale, bone consists of a hierarchical structure of mineral crystals (hard material) and collagen (soft material). Inspired by bone's nanoscale structure and properties, we design a nanocomposite with flexible pristine/polycrystalline graphene embedded in a hard Ni matrix. We model Ni graphene nanocomposites, with different structural arrangements for graphene in the Ni matrix. We use molecular dynamics to investigate the deformation of Ni-graphene nanocomposites under 3-point bending. We find that nanocomposites can deform approximately 30% more than pure Ni. The flexibility of the nanocomposite is optimally enhanced with a distance between graphene sheets greater than or equal to 3.05 nm. Polycrystalline graphene nanocomposites show approximately 15–20% improvement in bending modulus compared to pristine graphene nanocomposites. The increase in bending modulus of polycrystalline graphene nanocomposite is because polycrystalline graphene has higher interfacial shear strength compared to pristine graphene. We also find that the structural arrangement of graphene sheets is more important than increases in their volume fraction in the Ni matrix. These results suggest that graphene sheets scattered in the Ni-matrix is preferable to other structural arrangements. The results from this simulation could help in tuning nanocomposite with desired mechanical properties for various engineering applications. [ABSTRACT FROM AUTHOR]

Achilles tendinosis is primarily managed nonoperatively with activity modification and physiotherapy, although surgery can be required. This has classically involved surgical decompression of the Achilles tendon, although the use of radiofrequency microdebridement has been suggested as a novel minimally invasive alternative. We present a randomized controlled trial comparing radiofrequency microdebridement using the Topaz ® microdebrider wand and traditional surgical decompression. All patients with Achilles tendinosis referred to a single surgeon and meeting the inclusion criteria were invited to participate in our single-blinded, randomized controlled study. The Victorian Institute of Sports Assessment–Achilles (VISA-A) questionnaire and the visual analog scale were used as measures at baseline and 6 months postoperatively. From 2009 to 2014, 16 patients were randomized to traditional decompression treatment and 20 to Topaz ® treatment. All surgical procedures were performed as day-case procedures with the patient under general anesthetic by a single surgeon. No significant differences were found between the groups in demographic data. At 6 months after intervention, both groups demonstrated an improvement in the Victorian Institute of Sports Assessment–Achilles and visual analog scale scores compared with baseline, with no difference found between treatment modalities at 6 months. The Topaz ® microdebrider resulted in variable outcomes after surgery and is not without complications. Regarding the patient-reported outcome measures, Topaz ® conferred no additional benefit compared with traditional surgical decompression and we have stopped using Topaz ® in our treatment of Achilles tendinosis. [ABSTRACT FROM AUTHOR]

Polymeric composites have attracted increasing interest in fundamental studies and industrial applications due to their often-superior characteristics over conventional pure polymers. In this work, we studied the relationship between the rheological properties, critical in processing methods such as additive manufacturing, and the structure of a polymer-2D filler system by experiment and simulation methods. Considering the high-performance polymer polyetherketoneketone (PEKK) with 2D filler (mica) composite as an example, the effects of filler size, filler content, surface chemistry and shear rate were systematically investigated. It is demonstrated that the interaction between the polymer and 2D filler brings two different consequences on tuning the viscosity of polymer-filler composite. The stronger interaction increases the shear stress of the polymer-2D filler composite system, leading to higher viscosity. On the other hand, the stronger interaction can promote more adsorption of polymer chains on the surface and form ordered structure in short range, which will make the local polymer network disentangled and decreases the continuous viscosity from the polymer network for entangled polymer system. This work provides a fundamental understanding on the relationship between macroscopic rheological properties and the structural properties and energetics at molecular level of polymer-2D filler composite. [Display omitted] • Effect of size, fraction, and surface chemistry of 2D filler in polymer composite on rheological properties was studied. • Stronger interaction between polymer and 2D filler in polymer composite leads to higher viscosity. • Ordered structuring, induced by polymer adsorption, makes the local polymer network disentangle, decreasing viscosity. [ABSTRACT FROM AUTHOR]

Abstract: Increasing latex hypersensitivity among patients and health care workers has prompted the development of latex-free surgical gloves. Latex-free gloves must perform equally as the existing latex standard. We analyzed perforation rates in a clinical trial comparing latex and a latex-free alternative during primary hip and knee arthroplasty. The overall latex glove perforation rate was 8.4% compared with 21.6% for the latex-free alternative (χ 2 P < .001). The operation perforation rate for latex gloves was 34.4% compared with 80% for latex-free gloves (χ 2 P < .001). We suggest that the latex-free glove tested cannot provide a reliable barrier between the surgeon and the patient. As such, we question the safety of these gloves and the standards sets by the regulators. [Copyright &y& Elsevier]

Abstract: Cement mantle voids remain controversial with respect to survival of total hip arthroplasty. Void evolution is poorly understood, and attempts at void manipulation can only be empirical. We induced voids in a cement model simulating the constraints of the proximal femur. Intravoid pressure and temperature were recorded throughout polymerization, and the initial and final void volumes were measured. Temperature-dependent peak intravoid pressures and void volume increases were observed. After solidification, subatmospheric intravoid pressures were observed. The magnitude of these observations could not be explained by the ideal gas law. Partial pressures of the void gas at peak pressures demonstrated a dominant effect of gaseous monomer, thereby suggesting that void growth is a pressure-driven phenomenon resulting from temperature-dependent evaporation of monomer into existing trapped air voids. [Copyright &y& Elsevier]

The majority of ankle fractures are stable and can be treated without an operation, most commonly with cast immobilisation. Based on concerns regarding the risk of a venous thromboembolic event (VTE) while immobilised, there is currently debate as to whether these patients should receive VTE prophylaxis for the duration of treatment. Rates of pulmonary embolism (PE) in this patient group are unknown. This retrospective cohort study was designed to identify patients treated without an operation for ankle fracture and determine the occurrence of PE and inpatient mortality within 90 days of injury using the English National Health Service administrative databases. Logistic regression models were used to assess the influence of age, gender and Charlson co-morbidity score on these outcomes. We identified 14777 adult patients over a 54-month period (April 2007-September 2011) that met our linkage and inclusion criteria (isolated, unilateral closed ankle fracture that did not require hospitalisation). Mean age was 46.4 years (range 18-99) and the majority had a Charlson 0 score (97.7%). There were 32 (0.22%) PEs within 90 days of the fracture (including in one patient who subsequently died). After adjustment, Charlson score of ≥1 was associated with a greater risk of PE (Odds ratio = 11.97, p < 0.001) compared to Charlson 0. Risk for these patients was 2.08%. In total, fifteen patients (0.11%) died in hospital within 90 days. Pulmonary embolism is rare following ankle fractures treated without an operation. Patients with multiple co-morbidities are at a higher risk. Based on this evidence, an ankle fracture treated without an operation does not appear to be an indication for routine VTE prophylaxis. [ABSTRACT FROM AUTHOR]

Abstract: Background: The treatment of choice for intracapsular neck of femur (NOF) fractures in younger, more active patients remains unknown. Some surgeons advocate total hip replacement (THR). Aim: This study aimed to compare complications following THR and hemiarthroplasty using the Hospital Episode Statistics (HES) database in England. Method: Dislocation and revision rates were extracted for all patients with NOF fracture who underwent either cemented hemiarthroplasty or cemented THR between January 2005 and December 2008. To make a ‘like for like’ comparison all 3866 THR patients were matched to 3866 hemiarthroplasty patients (from a total of 41,343) in terms of age, sex and Charlson score. Results and conclusion: Eighteen-month dislocation was significantly higher in the THR group (2.4% vs. 0.5%, odds ratio (OR) 3.90 (2.99–5.05), p <0.001). This difference was sustained at the 4-year stage (2.9% vs. 0.9%, OR 3.18 (1.58–6.94), p =0.001) in a subset of patients with longer follow-up. There was no significant difference in revision rate up to 4 years (1.8% vs. 2.1%, OR 0.85 (0.46–1.55), p =0.666). In this national analysis of matched patients short- and medium-term dislocation rates following THR were significantly higher than following cemented hemiarthroplasty, without any difference in revision rates at 4 years. The low risk of dislocation may be acceptable in order to experience the apparent functional benefits of THR. [Copyright &y& Elsevier]

National guidelines recommend cemented hemiarthroplasty for intracapsular fractured neck of femur (NOF), based on evidence of less pain, better mobility and lower costs. We aimed to compare complications following cemented and cementless implants, using the national hospital episode statistics (HES) database in England. Dislocation, revision, return to theatre and medical complications were extracted for all patients with NOF fracture who underwent hemiarthroplasty between January 2005 and December 2008. To make a 'like for like' comparison all 30,424 patients with a cementless implant were matched to 30,424 cemented implants (from a total of 42,838) in terms of age, sex and Charlson co-morbidity score. In the cementless group, 18-month revision (1.62% versus 0.57% (OR 2.90, p<0.001)), 4-year revision (2.45% versus 1.11% (OR 2.28, p<0.001)) and 30-day chest infection (8.14% versus 7.23% (OR 1.14, p=0.028)) were significantly higher. Four-year dislocation rate was higher in cemented implants (0.60% versus 0.26% (OR 0.45, p<0.001)). No significant differences were seen in return to theatre or other medical complications. In this national analysis of matched patients mid-term revision and perioperative chest infection was significantly higher in the cementless group. This supports the published evidence and national guidelines recommending cement fixation of hemiarthroplasty. [ABSTRACT FROM AUTHOR]